Brake



F. C. FRANK Oct. 25, 1938.

BRAKE Filed Sept. 18, 1935 2 Sheets-Sheet l INVENTOR. I [2202mm CTFEQML ATTORNEY TII s v 7 Oct. 25,1938. F. c.' FRANK ,134,

- BRAKE Filed Sept. 18, 1935 2 Sheets-Sheet 2 ATTORNEY.

Patented Och 25, 1938 UNITED STATES .PATEN'l OFFICE BRAKE Application September 18, 1935, Serial No. 41,137

6 Claims.

This invention relates to brakes and more particularly to an airplane braking system having an improved arrangement for applying brakes either uniformly or differentially to the two 5 wheels of the airplane.

One of the objects of the invention is to provide an improved, hydraulic actuating system for the brakes of an airplane so arranged as to be operated by pedals mounted on the rudder l actuating mechanism and arranged to operate the brakes on opposite sides ofthe airplane corresponding to the sides on which the pedals are mounted.

One of the features of the arrangement shown L is the provision ofa pair of master cylinders designed for operating hydraulic brakes each separately mounted upon one of the rudder pedals. V

A further feature of the arrangement shown :0 is the provision of a substantially parallelogram arrangement by means of which the pedals operating the brakes are maintained always substantially in a comfortable operating position.

- Further objects and ieatures of the invention 1;; will be apparent after a reading of thesubjoined specification and claims and after a considera-v tion of the accompanying drawings in which:

Figure 1 is a view showing an airplane in which there is incorporated an arrangement according :0 to my invention;

' Figure 2 is a view in elevation showing the brake and rudder pedal arrangement for the airplane of Figure 1;

Figure 3 is a view partially in section showing :5 a portion or one of the pedals shown in Figure 2 and showing the master cylinder thereon;

Figure 4 is a view similar to Figure 3 but showing a modified arrangement of the master cyl- 1 L0 e i Figure 5 is a fragmentary view showing a modified arrangement of the valve to be used in a cylinder similar to that shown in Figure 3; and L5 Figure 6isaviewsimilartoFigure fi-showing mounted v 62 andthus is iorcedout through the conduit i5 'to the associated brake to apply it. I

The stirrups ll and-III carry projections 32 and 34 which are connected asby cables with the rudder i6 so as to operate the rudder.

Extending through openings in the lower end, of the stirrups l8 and 20 are shafts 36 and 38 5 which are mounted for rotation in said openings. The shaits 35 and 38 have riveted thereto, brake pedals 40 and 42 and carry: angularly disposed arms 44. The shaft 30 has secured to it (as by welding) lugs 46 and 48. Plvotally connected to the lugs 46 and 48 are master cylinders 50 and 52 each having a piston such as 54. The pistons are connected by piston rods 56, with the I arms 44'so that actuation of the pedals 4|! and 42 transmit force through the piston rods 56 to move the pistons 54 in the master cylinders 50 and 52 to operate the master cylinders andvthus transmit force through the fluid conduit i-5to operate the brakes. The master cylinder is provided with valve chambers 58 which are con:

nected by the conduits l5 with-the brakes. Thus -a source of supply. The source of supply comprises a conduit 80 which may be combined with a convenient reservoir to which the conduit leads. Positioned in the chamber- 58 soas to separate the conduit 60 from the main portion of the chamber is a check valve 62 so arranged as to allow fluid to flow freely into said main portion from the conduit 60, but to prevent the flow of liquid in the opposite direction. v A tube 64 leads from the chamber 58 on the same side of the valve 52 as the conduit 60. The tube 64 leads to a port 68 in the side of the master cylinder 50 and thus when the master piston 54 is in a released position (as shown in Figure 3) liquid may flow freely from the source of supply 60 through the conduit 64 and port 66 into the master cylinder and thence 1 through the chamber 58 and the conduit. I! to the brake cylinder.) Thus when the piston is in its reeither pedal 40 is depressed to operate its piston 54 through its piston rod 56, the port is covered so by the piston. The liquid acted on by the master cylinder piston, cannot then escape through the tube 54 nor can it escape past the check valve It is to be understood that when the rudder is operated through the stirrups I8 and 20 then due to the substantially parallelogram arrangement of the stirrups I8 and 20 and the links comprising the master cylinders 50 and 52 and their piston rods 56, the relative position of the pedals 40 and 42 on the stirrups I8 and 20 remain substantially unchanged. It is to be noted, however, that the length of the arm .44 is slightly longer than the distance between the pivotal axis of the stirrup and the pivotal axis of the master cylinder and thus the pedals 40 'and 42 move slightly with the natural movement of the toe as the stirrups are operated by the heel of the pilot. Thus pedals 4|] and 42 are always in a convenient position so that the pilot may depress and rotate them relative to the stirrups and thus apply the brakes.

Latches are provided for holding the brakes applied when the airplane is on the ground as in parking. These latches comprise (see Figure 3) toothed members 90 fixed to the brake pedals All and 42, dogs 92 pivoted on the stirrups I8 and 20 and normally held out of contact with the members 90: by springs 94 also connected to the stirrups I8 and 20. When it is desired to latch any brakein' any applied position a pull is exerted on a cable 96 which tensions a spring 98 -having greater force than the spring 94 thus moving the dog 92 into contact with the teeth of the toothed member 80 and holding the brake in-the applied position.

In Figure- 4 there is shown an arrangement similar to that shown in Figure 3 and similar parts have been designated by like numerals with the addition of I00. The master cylinder I50 includes a castingJ'IIl through which there is inserted a thin sleeve I52 provided with'a port I66. screw cap I14 and the piston is formed in two parts, comprising the piston' proper I54 and the piston rod connection I55 threaded into the piston proper. The piston rod I56 has a lost motion connection as at I51 with the member I55. A threaded and bored coupling member I59 is welded to the upper end of the sleeve I 52 and has connected thereto a conduit II5 leading to the brakes. The casting III! is formed with an annular recess I65 which registers with the port I66 and connected to this recess I65 is a conduit I66 leading to the source of supply. It may be seen that with this arrangement machining of parts other than sleeve I52 and the piston I54 is minimized. It is also to be noted that "with this arrangement no check valves need to be used. The lost motion connection between the piston rod I56 and the member I55 is intended to prevent the drawing in of air at the wheel.

cylinders such as might otherwise occur by reason of the omissionv of the check valve.

In the arrangement shown in Figure 5 the check valve 262 is bevel shaped and is urged toward its seat by a spring 263 which 'bears at its opposite end on a member 265 threaded into the casing 218.

In the/arrangement shown in Figure 6 the valve 362 rests upon a seat 386 formed as an insert and secured within the casing 318'.

His believed that the operation 01' my device will be apparent from the above disclosure.

Operation of the stirrups I6 and 20 controls the rudder through any appropriate connections.

. Movement of the foot pedals 46 and 42' relative to the stirrups I6 and 20 operates the master cylinder to force fluid from said cylinders "throughthe conduit I5 to the brakes II and thus The sleeve is clamped in position by a 1 controls the braking of the wheels of the airplane. I

It is to be understood that the above described embodiments of my invention are for the purpose of illustration only and various changes may be made therein without departingfrom the spirit and scope of the invention.

I claim: r

1. A brakesystem for an airplane comprising a pair'of rudder pedals in the form of stirrups, a pair of brake pedals one mounted on each of said rudder pedals, a master cylinder mounted on each of 'said'rudder pedals, brakes, means whereby movement of each of said brake pedals relative to its associated rudder pedal actuates one said master cylinder, and means whereby actuation of each of said master cylinders operates one of said brakes, further characterized in that there is provided a brake pedal arm operated by each brake pedal and in that each master cylinder is pivoted at its upper end, normally has its longitudinal axis substantially vertical, and has a piston in the lower end thereof connected by a piston rod with said brake pedal arm so that the piston is arranged to be moved upward upon movement of the brake pedal, the link comprising said master cylinder and its piston being disposed substantially parallel to the stirrup but the brake pedal arm being longer than the distance between the pedal axis of the stirrup and the pedal axis for the master cylinder, whereby movement of the rudder pedals in controlling the rudder causes a corresponding movement of the pivotal axis of the brake pedal but a differential movement of the opposite end of the brake pedal.

2. A braking system for an airplane comprising a pair of rudder pedals in theform of stirrups, a pair of brake pedals one mounted pivotally on each of said rudder pedals, a master cylinder mounted .on each of said rudder pedals, brakes,

means whereby movement of each of said brake pedals relative to its associated rudder pedal actuates its associated master cylinder, and means whereby'actuation of each of said master cylinders operates one of said brakes, further characterized in that the master cylinder is provided with a piston and together with the piston acterized in that each master cylinder is pro-- vided with'a piston and together with the piston comprises a link disposed substantially parallel to the stirrup, and in that there is provided a brake pedal arm pivotally connected to each said piston rod which is longer than the distance between the pivotal axis of the stirrup and the pivotal axis of the master cylinder.

4. In a control system for a vehicle, a control member swin'gably mounted on the vehicle frame, a brake pedal mounted on the end of the control member swingable therewith and operable to apply a brake when the control member is in any of its several positions, and means for maintaining said brake pedal in substantially parallel relation to any of the several positions it occupies as said control member is moved, said lastnamed means comprising a brake operating leve'r secured to said pedal, a master cylinder hinged to the vehicle frame in spaced relationship to the'swingable mounting of the control member. a piston in said cylinder and a piston 1 rod connected to the piston and said lever, said master cylinder, piston and piston rod being disposed substantially parallel to said control member.

5. In a controlsystem for a vehicle, a control member pivotally mounted on the vehicle frame, a brake pedal mounted on the freeend of the member, a lever secured to said pedal, and a master cylinder, piston and piston rod assembly having one end pivotally mounted on the vehicle frame and one end connected to said lever.

6. In a control system for a vehicle, a control member pivotally mounted on the vehicle frame, a brake pedal mounted on the free end of the member, a lever secured to said pedal, and a master cylinder, piston, and piston rod assembly having one end pivotally mounted on the vehicle frame and one end connected to said lever, said member, lever, frame, and master cylinder and piston and piston rod assembly constituting a four bar linkage to position said pedal in accordance with the position of said member. 

